Vehicle chassis frame side rail of improved cross section

Abstract

The invention relates to a vehicle, notably a motor vehicle, chassis frame side rail made up of two section pieces of U-shaped cross section, welded together by longitudinal connecting tabs juxtaposed contiguously and more or less perpendicularly extending the ends of the branches of the U, in which each section piece has, between each of the tabs and the branches of the U that it extends, a joining area that forms two separate longitudinal plastic hinges that deform if the side rail is deformed by longitudinal compression so as to keep the welded joint between the tabs intact.

What is claimed is: 
     
       1. A chassis frame side rail of a vehicle, said side rail comprising two opposing section pieces, each section piece having a U-shaped cross section, and a pair of opposing welding longitudinal connecting tabs that extend ends of a pair of opposing branches of the respective section piece substantially perpendicularly, the connecting tabs of the opposing section pieces welded together to attach the section pieces together, wherein each section piece further comprises:
 a joining area formed between each one of the longitudinal connecting tabs and a respective one of the branches of the respective section piece that the respective connecting tab extends from, each joining area providing two separate longitudinal plastic hinges upon a longitudinal compressive impact to the side rail such that the side rail deforms in an accordion like manner so as to keep the attachment by welding of the longitudinal connecting tabs intact, wherein each joining area comprises a curve having a radius greater than or equal to 12 mm formed between the respective longitudinal connecting tab and the respective branch of the respective section piece. 
 
     
     
       2. The chassis frame side rail according to  claim 1 , wherein the curve has a radius between 15 mm and 19 mm. 
     
     
       3. The chassis frame side rail according to  claim 2 , wherein each curved joining area is replaced with a beveled section between the respective longitudinal connecting tab and the respective branch from which the respective connecting tab extends, wherein an angle formed between the respective branch and the bevel section provides one of the plastic hinges, and the angle formed between the bevel section and the respective longitudinal connecting tab provides the second plastic hinge. 
     
     
       4. The chassis frame side rail according to  claim 1 , further comprising a plate attached to an end of the side rail at an edge of an end of each longitudinal connecting tab, wherein the end edges of each opposing longitudinal connecting tab of the same section piece are deformed in an opposite direction with respect to each other at the attachment to the plate, such that deformation of the side rail is promoted by forming accordion folds in opposite directions upon the longitudinal compressive impact to the side. 
     
     
       5. The chassis frame side rail according to  claim 1 , wherein the attachment by welding of the longitudinal connecting tabs comprises of a plurality of welding points. 
     
     
       6. A chassis frame of a vehicle, said frame comprising:
 two side rails, each side rail comprising:
 two opposing section pieces, each section piece having a U-shaped cross section, and a pair of opposing welding longitudinal connecting tabs that extend ends of a pair of opposing branches of the respective section piece substantially perpendicularly, the connecting tabs of the opposing section pieces welded together to attach the section pieces together, wherein each section piece further comprises:
 a joining area formed between each one of the longitudinal connecting tabs and a respective one of the branches of the respective section piece that the respective connecting tab extends from, each joining area providing two separate longitudinal plastic hinges upon a longitudinal compressive impact to the side rail such that the side rail deforms in an accordion like manner so as to keep the attachment by welding of the longitudinal connecting tabs intact, wherein each joining area comprises a curve having a radius greater than or equal to 12 mm formed between the respective longitudinal connecting tab and the respective branch of the respective section piece. 
 
 
 
     
     
       7. A motor vehicle, said motor vehicle comprising:
 a chassis frame of a vehicle, said frame comprising:
 two side rails, each side rail comprising:
 two opposing section pieces, each section piece having a U-shaped cross section, and a pair of opposing welding longitudinal connecting tabs that extend ends of a pair of opposing branches of the respective section piece substantially perpendicularly, the connecting tabs of the opposing section pieces welded together to attach the section pieces together, wherein each section piece further comprises:
 a joining area formed between each one of the longitudinal connecting tabs and a respective one of the branches of the respective section piece that the respective connecting tab extends from, each joining area providing two separate longitudinal plastic hinges upon a longitudinal compressive impact to the side rail such that the side rail deforms in an accordion like manner so as to keep the attachment by welding of the longitudinal connecting tabs intact, wherein each joining area comprises a curve having a radius greater than or equal to 12 mm formed between the respective longitudinal connecting tab and the respective branch of the respective section piece.